rs1555260207

Variant names:

• chr12-120978770-TG-T
• rs1555260207
• NM_000545.8:c.4delG

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PM2_Supporting PP4

This summary comes from the ClinGen Evidence Repository: The c. 4delG variant in the HNF1 homeobox A gene, HNF1A, causes a frameshift in the protein at codon 2 (NM_000545.6), adding 4 novel amino acids before encountering a stop codon (p.(Val2PhefsTer4)). This variant, located in biologically-relevant exon 1 of 10, is predicted to lead to nonsense mediated decay in a gene in which loss-of-function is an established disease mechanism (PVS1; PMID:23348805). Additionally, the variant is absent from gnomAD v2.1.1 (PM2_Supporting). Lastly, this variant was identified in an individual with a clinical history highly specific for HNF1A-MODY (MODY probability calculator result >50%, negative genetic testing for HNF4A) (PP4; internal lab contributors). In summary, this variant meets the criteria to be classified as pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 1.1, approved 9/30/2021): PVS1, PM2_Supporting, PP4. LINK:https://erepo.genome.network/evrepo/ui/classification/CA658658175/MONDO:0015967/017

• Frequency: Genomes: not found (cov: 32)
• Consequence: HNF1A NM_000545.8 frameshift
• Clinical Significance: Pathogenic reviewed by expert panel P:3
• Conservation: PhyloP100: 8.40
• Publications: 0 publications found

Genes affected

HNF1A (HGNC:11621): (HNF1 homeobox A) The protein encoded by this gene is a transcription factor required for the expression of several liver-specific genes. The encoded protein functions as a homodimer and binds to the inverted palindrome 5'-GTTAATNATTAAC-3'. Defects in this gene are a cause of maturity onset diabetes of the young type 3 (MODY3) and also can result in the appearance of hepatic adenomas. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Apr 2015]

HNF1A-AS1 (HGNC:26785): (HNF1A antisense RNA 1)

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PVS1: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000545.8. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HNF1A	NM_000545.8	MANE Select	c.4delG	p.Val2PhefsTer4	frameshift	Exon 1 of 10	NP_000536.6
	HNF1A	NM_001306179.2		c.4delG	p.Val2PhefsTer4	frameshift	Exon 1 of 10	NP_001293108.2
	HNF1A	NM_001406915.1		c.4delG	p.Val2PhefsTer4	frameshift	Exon 1 of 9	NP_001393844.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HNF1A	ENST00000257555.11	TSL:1 MANE Select	c.4delG	p.Val2PhefsTer4	frameshift	Exon 1 of 10	ENSP00000257555.5
	HNF1A	ENST00000544413.2	TSL:1	c.4delG	p.Val2PhefsTer4	frameshift	Exon 1 of 10	ENSP00000438804.1
	HNF1A	ENST00000538626.2	TSL:1	n.122delG		non_coding_transcript_exon	Exon 1 of 2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Pathogenic

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
1	-	-	Maturity onset diabetes mellitus in young (1)
1	-	-	Monogenic diabetes (1)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		8.4
Mutation Taster		=3/197	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1555260207; hg19: chr12-121416573;